The present invention disclosed herein relates to a driving signal generator, and more particularly, to a current switch driving circuit generating a signal for driving a current switch, and a digital-to-analog converter (DAC) using the same.
Various factors, such as matching characteristics between elements, glitches, switching schemes or the like, exert influence on the dynamic performance of a current-driven type DAC. Among those, a factor having the biggest influence thereon is output impedance of a unit current source, which is a basic component of the current-driven type DAC. The higher the output impedance of the unit current source, the better the spurious free dynamic range (SFDR) characteristics.
As compared to a typical current-driven type DAC, the magnitude of an output voltage of a DAC for video signal processing is greater than that of the typical current-driven type DAC. In case of the output voltage of a large magnitude, that is, high output voltage, an operation region of transistors included in a DAC may be a linear region, rather than a saturation region. In this case, the transistors, included in the DAC, fail to amplify the output impedance of a unit current source. Thus, if a DAC has an output voltage of a large magnitude, the output impedance of a unit current source is lowered, thereby deteriorating the SDFR characteristics of the DAC.